1. Field of the Invention
This invention relates to a method of fabricating a printing head for use in a thermal printing system for thermally recording on thermally sensitive recording materials.
2. Description of the Prior Art
In a well-known thermal printing system, an information being printed can be printed on a thermally sensitive recording material by converting an electric current representative of the information into a signal in the form of thermal energy and applying the signal to the thermally sensitive recording material by means of a printing head associated with the material. There is well known such a printing head comprising a substrate made of a material having a high resistivity, a plurality of resistive elements selectively arranged on said substrate for converting an electric signal into a signal in the form of thermal energy, and electric conducters arranged on the substrate and connected with the resistive elements for feeding the electric signal thereto. In conventional methods of fabricating such a printing head, with the substrate being made of an insulating material such as glass, resistive elements and electric conductors are provided on the substrate by use of vacuum evaporation or sputtering or circuit printing process, or with the substrate being made of semiconductor material, resistive elements and electric conductors are provided on the substrate by use of diffusion process.
Since the physical dimensions of such a printing head require that the resistive elements are formed to have minute dimensions such as in the order of less than 0.5 mm, however, the conventional methods as mentioned above have the disadvantages that fabricating yield is poor and complicated processes are involved and that the resultant resistive elements are incomplete in different points such as accuracy, adhesive property to the substrate, unchangeability of resistance and wear-proof, which is dependent on the thickness of the elements.